Note: Descriptions are shown in the official language in which they were submitted.
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METHOD OF MODIFYING
THE RHEOLOGY OF A THERMOPLASTIC RESIN
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to methods of
modifying the rheology of thermoplastic resins and in
particular to compositions containing thermoplastics
and polyolefin containing interpolymers.
2. Description of the Prior Art
Thermoplastics, such as polyolefins are often used
in applications such as blown film, cast films, solid
sheets, injection molded articles, thermoformed
articles, blow molded articles, rotomolded articles,
compression molded articles, and functional films. In
many processing operations, the throughput rate, melt
elasticity, processibility and physical properties such
as strength properties, heat seal properties,
rheological properties, diffusion properties, and
optical properties of the polyolefins do not meet the
needs of the end user and/or are slow and/or difficult
to process.
As a non-limiting example, the low shear viscosity
of many thermoplastics is too low under normal
processing conditions and thermoformed articles made
from the polyolefin are non-uniform with thin sections
that create weak points in the structure of the
article.
In another non-limiting example, many
thermoplastics can be too elastic under processing
conditions resulting in poor processibility and low
throughput rates.
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As a further non-limiting example, many
thermoplastics can be too viscous under processing
conditions, also resulting in poor processibility and
low throughput rates.
Thus, there is a need in the art for
thermoplastic, and in particular polyolefin and
elastomer compositions that provide an adequate balance
between viscous and elastic properties to provide good
processibility while maintaining good physical
properties such as strength properties, heat seal
properties, and optical properties.
SUMMARY OF THE INVENTION
The present invention provides a method of
modifying the rheology of a thermoplastic resin. The
method includes the steps of providing a thermoplastic
resin and blending interpolymer resin particles with
the thermoplastic resin. The interpolymer resin
contains a styrenic polymer intercalated within a
polyolefin, such that the thermoplastic resin is
present as a continuous phase and the interpolymer
resin is present as a dispersed phase.
The present invention also provides a rheology
modified thermoplastic resin made according to the
above described method.
DETAILED DESCRIPTION OF THE INVENTION
Other than in the operating examples or where
otherwise indicated, all numbers or expressions
referring to quantities of ingredients, reaction
conditions, etc. used in the specification and claims
are to be understood as modified in all instances by
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the term "about". Accordingly, unless indicated to the
contrary, the numerical parameters set forth in the
following specification and attached claims are
approximations that can vary depending upon the desired
properties, which the present invention desires to
obtain. At the very least, and not as an attempt to
limit the application of the doctrine of equivalents to
the scope of the claims, each numerical parameter
should at least be construed in light of the number of
reported significant digits and by applying ordinary
rounding techniques.
Notwithstanding that the numerical ranges and
parameters setting forth the broad scope of the
invention are approximations, the numerical values set
forth in the specific examples are reported as
precisely as possible. Any numerical values, however,
inherently contain certain errors necessarily resulting
from the standard deviation found in their respective
testing measurements.
Also, it should be understood that any numerical
range recited herein is intended to include all sub-
ranges subsumed therein. For example, a range of "1 to
10" is intended to include all sub-ranges between and
including the recited minimum value of 1 and the
recited maximum value of 10; that is, having a minimum
value equal to or greater than 1 and a maximum value of
equal to or less than 10. Because the disclosed
numerical ranges are continuous, they include every
value between the minimum and maximum values. Unless
expressly indicated otherwise, the various numerical
ranges specified in this application are
approximations.
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As used herein, the terms "chi" or "X", refer to
the thermodynamic interaction parameter calculated from
the differences in the solubility parameter (6) for
each of two materials, determined at 20 C.
As used herein, the term "continuous phase" refers
to a material into which an immiscible material is
dispersed. In embodiments of the present invention,
polyolefins provide a continuous phase into which a
monomer mixture is dispersed. In other embodiments of
the invention, polyolefin particles are dispersed in an
aqueous continuous phase during polymerization.
As used herein, the term "dispersed phase" refers
to a material in droplet or particulate form which is
distributed within an immiscible material. In
embodiments of the present invention, a monomer mixture
provides a dispersed phase in a continuous phase
containing one or more polyolefins. In other
embodiments of the invention, the present interpolymer
resin particles make up a dispersed phase within a
thermoplastic, in many cases a polyolefin, continuous
phase.
As used herein, the term "elastomer" refers to
materials that have the ability to undergo deformation
under the influence of a force and regain its original
shape once the force is removed. In many embodiments
of the invention, elastomers include homopolymers and
copolymers containing polymerized residues derived from
isoprene and/or butadiene.
As used herein, the term "intercalated" refers to
the insertion of one or more polymer molecules within
the domain of one or more other polymer molecules
having a different composition. In embodiments of the
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invention, as described herein below, styrenic polymers
are inserted into polyolefin particles by polymerizing
a styrenic monomer mixture within the polyolefin
particles.
As used herein, the terms "(meth)acrylic" and
"(meth)acrylate" are meant to include both acrylic and
methacrylic acid derivatives, such as the corresponding
alkyl esters often referred to as acrylates and
(meth)acrylates, which the term "(meth)acrylate" is
meant to encompass.
As used herein, the term "monomer" refers to small
molecules containing at least one double bond that
reacts in the presence of a free radical polymerization
initiator to become chemically bonded to other monomers
to form a polymer.
As used herein, the term, "olefinic monomer"
includes, without limitation, a-olefins, and in
particular embodiments ethylene, propylene, 1-butene,
1-hexene, 1-octene and combinations thereof.
As used herein, the term "polyolefin" refers to a
material, which is prepared by polymerizing a monomer
composition containing at least one olefinic monomer.
As used herein, the term "polyethylene" includes,
without limitation, homopolymers of ethylene and
copolymers of ethylene and one or more of propylene, 1-
butene, 1-hexene and 1-octene.
As used herein, the term "polymer" refers to
macromolecules composed of repeating structural units
connected by covalent chemical bonds and is meant to
encompass, without limitation, homopolymers, random
copolymers, block copolymers and graft copolymers.
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As used herein, the term "styrenic polymer" refers
to a polymer derived from polymerizing a mixture of one
or more monomers that includes at least 50 wt.% of one
or more monomers selected from styrene, p-methyl
styrene, a-methyl styrene, tertiary butyl styrene,
dimethyl styrene, nuclear brominated or chlorinated
derivatives thereof and combinations thereof.
As used herein, the term "solubility parameter" of
"5" refers to the Hildebrand Solubility Parameter.
As used herein, the term "thermoplastic" refers to
a class of polymers that soften or become liquid when
heated and harden when cooled. In many cases,
thermoplastics are high-molecular-weight polymers that
can be repeatedly heated and remolded. In many
embodiments of the invention, thermoplastic resins
include polyolefins and elastomers that have
thermoplastic properties.
As used herein, the terms "thermoplastic
elastomers" and "TPE" refer to a class of copolymers or
a blend of polymers (in many cases a blend of a
thermoplastic and a rubber) which includes materials
having both thermoplastic and elastomeric properties.
As used herein, the terms "thermoplastic olefin"
or "TPO" refer to polymer/filler blends that contain
some fraction of polyethylene, polypropylene, block
copolymers of polypropylene, rubber, and a reinforcing
filler. The fillers can include, without limitation,
talc, fiberglass, carbon fiber, wollastonite, and/or
metal oxy sulfate. The rubber can include, without
limitation, ethylene-propylene rubber, EPDM (ethylene-
propylene-diene rubber), ethylene-butadiene copolymer,
styrene-ethylene-butadiene-styrene block copolymers,
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styrene-butadiene copolymers, ethylene-vinyl acetate
copolymers, ethylene-alkyl (meth)acrylate copolymers,
very low density polyethylene (VLDPE) such as those
available under the Flexomer0 resin trade name from the
Dow Chemical Co., Midland, MI, styrene-ethylene-
ethylene-propylene-styrene (SEEPS). These can also be
used as the materials to be modified by the
interpolymer to tailor their rheological properties.
Unless otherwise specified, all molecular weight
values are determined using gel permeation
chromatography (GPO) using appropriate polystyrene
standards. Unless otherwise indicated, the molecular
weight values indicated herein are weight average
molecular weights (Mw).
The present invention provides a method of
modifying the rheology of a thermoplastic resin, in
many embodiments a polyolefin resin. The method
generally includes the steps of providing a
thermoplastic resin and blending interpolymer resin
particles that contain a styrenic polymer intercalated
within a polyolefin, such that the thermoplastic resin
is present as a continuous phase and the interpolymer
resin is present as a dispersed phase. The present
method provides a rheology modified thermoplastic
resin.
In embodiments of the invention, the thermoplastic
resin includes a polyolefin. In other embodiments of
the invention, the thermoplastic resin is made up of
one or more polyolefin resins.
Any suitable polyolefin resin can be used in the
present method. In many embodiments of the invention,
the polyolefin resin includes at least one
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polyethylene. In particular embodiments, the
polyethylene is one or more of linear low density
polyethylene and low density polyethylene.
In some embodiments of the invention, the
polyolefin of the thermoplastic resin includes a
copolymer derived from one or more olefinic monomers
and one or more monomers selected from, without
limitation, C1-C4 alkyl (meth)acrylates,
(meth)acrylonitrile, vinyl acetate, butadiene,
isoprene, styrene, and combinations thereof.
In other embodiments of the invention, the
polyolefin of the thermoplastic resin includes one or
more polymers selected from homopolymers of any C2-C8
linear or branched a-olefins; copolymers of ethylene
and one or more C3-C8 a-olefins; copolymers of one or
more C2-C8 linear or branched a-olefins and vinyl
acetate and/or C1-C8 alkyl esters of (meth)acrylic
acid, and combinations thereof.
The thermoplastic resin can include blends of
different resins. As a non-limiting example, the
thermoplastic resin can include a blend of two or more
polyolefins and elastomers, and in particular two or
more of polyethylene, polypropylene, ethylene-vinyl
acetate copolymers, ABS, polycarbonate, TPO, TPE,
polyphenylene oxide, styrene-acrylonitrile copolymers,
styrene butadiene block copolymer (SBC), ethylene-
alkyl(meth)-acrylate copolymers, and other such
materials.
The thermoplastic resin is present in the rheology
modified thermoplastic resin at a level of at least
about 30 wt.%, in some instances at least about 40
wt.%, in other instances at least about 50 wt.%, in
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some situations at least about 60 wt.%, in other
situations at least about 65 wt.%, in some cases at
least about 70 wt.% and in other cases at least about
75 wt.% of the rheology modified thermoplastic resin.
Also, the thermoplastic resin is present in the
rheology modified thermoplastic resin at a level of up
to about 99.9 wt.%, in some cases up to about 99.5
wt.%, in other cases up to about 99 wt.%, in some
instances up to about 98 wt.%, in other instances up to
about 97 wt.%, in some situations up to about 95 wt.%
and in other situations up to about 90 wt.% of the
rheology modified thermoplastic resin. The amount and
types of thermoplastic resin present in the rheology
modified thermoplastic resin is determined based on the
desired end use and physical properties. The amount of
thermoplastic resin in the rheology modified thermo-
plastic resin can be any value or range between any of
the values recited above.
The dispersed phase in the present invention
includes non-expandable interpolymer resin particles
having little or no gel content. In embodiments of the
invention, the interpolymer resin particles can have,
at least in part, a crystalline morphology. The
interpolymer resin includes a polyolefin and an
intercalated polymer that contains repeat units derived
from one or more styrenic monomers.
In particular embodiments of the invention, the
interpolymer resin particles can include the unexpanded
interpolymer resin particles described in U.S. Pat. No.
7,411,024.
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In embodiments of the invention, the interpolymer
resin particles include at least about 20, in some
cases at least about 25, in other cases at least about
30, in some instances at least about 35 and in other
instances at least about 40 wt.% of one or more
polyolefins. Also, the interpolymer resin particles
include up to about 80, in some instances up to about
60, in some cases up to about 55, and in other cases up
to about 50 wt.% of one or more polyolefins. The
polyolefin content of the interpolymer resin particles
can be any value or range between any of the values
recited above.
In embodiments of the invention, the polyolefin in
the interpolymer resin particles includes one or more
of polyethylene, polypropylene, thermoplastic olefins
(TPO's), and thermoplastic elastomers (TPE's) resins.
In particular embodiments of the invention, the
polyethylene is one or more of linear low density
polyethylene and low density polyethylene. Suitable
polyolefins are those that provide the desirable
properties in the present interpolymer resin particles
as described below.
In embodiments of the invention, the polyethylene
can include a homopolymer of ethylene, ethylene
copolymers that include at least 50 mole % and in some
cases at least 70 mole %, of an ethylene unit and a
minor proportion of a monomer copolymerizable with
ethylene, ethylene-vinyl acetate copolymers, HDPE,
LDPE, LLDPE, VLDPE, and a blend of at least 50% by
weight, preferably at least 60% by weight, of the
ethylene homopolymer or copolymer with another polymer.
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Non-limiting examples of monomers copolymerizable
with ethylene include vinyl acetate, vinyl chloride,
propylene, butene, hexene, (meth)acrylic acid and its
esters, butadiene, isoprene, styrene and combinations
thereof.
Non-limiting examples of the other polymers that
may be blended with the ethylene homopolymer or
copolymer include any polymer compatible with it. Non-
limiting examples include polypropylene, polybutadiene,
polyiso-prene, polychloroprene, chlorinated
polyethylene, polyvinyl chloride, a styrene/butadiene
copolymer, a vinyl acetate/ethylene copolymer, an
acrylonitrile/-butadiene copolymer, a vinyl
chloride/vinyl acetate copolymer, etc. Especially
preferred species are polypropylene, polybutadiene,
styrene/butadiene copolymer and combinations thereof.
Non-limiting examples of polyethylene that can be
included in the interpolymer resin particles include
low-, medium-, and high-density polyethylene, an
ethylene vinyl acetate copolymer, an ethylene/propylene
copolymer, a blend of polyethylene and polypropylene, a
blend of polyethylene and an ethylene/vinyl acetate
copolymer, and a blend of polyethylene and an
ethylene/propylene copolymer.
In embodiments of the invention, the polyethylene
resin particles used to form the interpolymer resin
particles of the invention can have a melt index (MI)
of about 0.2 to 4 g/10 minutes under Condition I,
190 C, 2.16 kg (equivalent to 11.9 g/10 minutes under
Condition G, 230 C 5.0 kg); a number average molecular
weight of 20,000 to 60,000; an intrinsic viscosity, at
75 C in xylene, of 0.8 to 1.1; a density of 0.910 to
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0.940 g/cm3, and a VICAT softening temperature greater
than 85 C.
In embodiments of the invention, the polyolefin of
the interpolymer resin has a VICAT softening
temperature greater than 85 C, in some cases at least
about 90 C and in other cases at least about 95 C and
can be up to about 115 C.
In embodiments of the invention, the polyolefin of
the interpolymer resin has a melt flow of at least 0.2,
in some cases at least about 0.5, in other cases at
least about 1.0, in some instances at least about 2.1,
in other instances at least about 2.5, in some
situations at least about 3.0 and in other situations
at least about 4.0 g/10 minutes (230 C, 2.16 kg under
ASTM D-1238).
The styrenic polymer is a polymer derived from
polymerizing a monomer mixture of one or more styrenic
monomers and optionally one or more other monomers.
Any suitable styrenic monomer can be used in the
invention. Suitable styrenic monomers are those that
provide the desirable properties in the present
interpolymer resin particles as described below. Non-
limiting examples of suitable styrenic monomers include
styrene, p-methyl styrene, a-methyl styrene, ethyl
styrene, vinyl toluene, tertiary butyl styrene,
isopropylxylene, dimethyl styrene, nuclear brominated
or chlorinated derivatives thereof and combinations
thereof.
When the monomer mixture includes other monomers,
the styrenic monomers are present in the monomer
mixture at a level of at least 50%, in some cases at
least 60% and in other cases at least 70% and can be
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present at up to 99%, in some cases up to 95%, in other
cases up to 90%, and in some situations up to 85% by
weight based on the monomer mixture. The styrenic
monomers can be present in the monomer mixture at any
level or can range between any of the values recited
above.
Suitable other monomers that can be included in
the monomer mixture include, without limitation, maleic
anhydride, C1-C4 alkyl (meth)acrylates, acrylonitrile,
vinyl acetate, and combinations thereof.
When the monomer mixture includes other monomers,
the other monomers are present in the monomer mixture
at a level of at least 1%, in some cases at least 5%,
in other cases at least 10%, in some instances at least
15%, in other instances at least 20%, in some
situations at least 25% and in other situations at
least 30% and can be present at up to 50%, in some
cases up to 40%, and in other cases up to 30% by weight
based on the monomer mixture. The other monomers can be
present in the monomer mixture at any level or can
range between any of the values recited above.
In embodiments of the invention, the interpolymer
resin particles include at least about 40, in some
cases at least about 45 and in other cases at least
about 50 wt.% of one or more styrenic polymers. Also,
the interpolymer resin particles include up to about
80, in some cases up to about 75, in other cases up to
about 70, in some instances up to about 65 and in other
instances up to about 60 wt.% of one or more styrenic
polymers. The styrenic polymer content of the
interpolymer resin particles can be any value or range
between any of the values recited above.
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In embodiments of the invention, cross-linking of
the polyolefin resin particles is minimized or
eliminated as reflected by the gel content in the
interpolymer resin. In particular embodiments of the
invention, the gel content of the interpolymer resin is
0 and can be up to about 1.5 wt.%, in other cases up to
about 1.0 wt.%, in other cases up to about 0.8 wt.% and
in some instances up to about 0.5 wt.%. The gel
content of the interpolymer resin can range between 0
and any of the values recited above.
In embodiments of the invention, the VICAT
softening temperature of the interpolymer resin
particles can be at least about 90 C and in some cases
at least about 95 C and can be up to about 115 C, in
some cases up to about 110 C and in other cases at
least about 105 C. The VICAT softening temperature of
the interpolymer resin particles can be any value or
range between any of the values recited above.
In embodiments of the invention, the melt index
value of the interpolymer resin particles can be at
least about 0.2, in some cases at least about 0.5, in
other cases at least about 1, in some instances at
least about 2.5 and in other instances at least about 5
g/10 minutes (Condition G) and can be up to about 35,
in some cases up to about 30, in other cases up to
about 25, in some instances up to about 20 and in some
instances up to about 15 g/10 minutes (Condition G).
The melt index value of the interpolymer resin
particles can be any value or range between any of the
values recited above.
In embodiments of the invention, the interpolymer
resin particles are prepared using a process that
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includes: providing the above described polyolefin
resin particles suspended in an aqueous medium;
minimizing or eliminating cross-linking in the
polyolefin resin particles; adding to the aqueous
suspension a monomer mixture that includes a vinyl
aromatic monomer, and a polymerization initiator for
polymerizing the monomer mixture within the polyolefin
resin particles; and polymerizing the monomer mixture
in the polyolefin resin particles to form the
interpolymer resin particles.
In embodiments of the invention, the interpolymer
resin particles are formed as follows: in a reactor,
the polyolefin resin particles are dispersed in an
aqueous medium prepared by adding 0.01 to 5%, in some
cases 2 to 3% by weight based on the weight of the
water of a suspending or dispersing agent such as water
soluble high molecular materials, e.g., polyvinyl
alcohol, methyl cellulose, and slightly water soluble
inorganic materials, e.g., calcium phosphate or
magnesium pyrophosphate, and then the vinyl aromatic
monomers are added to the suspension and polymerized
inside the polyolefin resin particles to form an
interpenetrating network of polyolefin and vinyl
aromatic monomers.
Any of the conventionally known and commonly used
suspending agents for polymerization can be employed.
These agents are well known in the art and may be
freely selected by one skilled in the art. Water is
used in an amount generally from 0.7 to 5, in many
cases 3 to 5 times that of the starting polyolefin
particles added to the aqueous suspension, on a weight
basis.
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When the polymerization of the vinyl aromatic
monomer is completed, the polymerized vinyl aromatic
resin is uniformly dispersed inside the polyolefin
particles.
Methods of preparing the interpolymer resin
particles are disclosed, as a non-limiting example, in
U.S. Pat. No. 7,411,024.
The interpolymer resin particles of the invention
may suitably be coated with compositions comprising
silicones, metal or glycerol carboxylates, suitable
carboxylates are glycerol mono-, di- and tri-stearate,
zinc stearate, calcium stearate, and magnesium
stearate; and mixtures thereof. Examples of such
compositions may be those disclosed in GB Patent No.
1,409,285 and in Stickley U.S. Pat. No. 4,781,983. The
coating composition can be applied to the interpolymer
resin particles via dry coating or via a slurry or
solution in a readily vaporizing liquid in various
types of batch and continuous mixing devices. The
coating aids in transferring the interpolymer resin
particles easily through the processing equipment.
The interpolymer resin particles can contain other
additives, which can include, without limitation, chain
transfer agents, nucleating agents, agents that enhance
biodegradability and other polymers.
Suitable chain transfer agents include, but are
not limited to, C2-15 alkyl mercaptans, such as n-
dodecyl mercaptan, t-dodecyl mercaptan, t-butyl
mercaptan and n-butyl mercaptan, and other agents such
as pentaphenyl ethane and the dimer of a-methyl
styrene, and combinations thereof.
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Suitable nucleating agents, include, but are not
limited to, polyolefin waxes. The polyolefin waxes,
which include without limitation, polyethylene waxes,
have a weight average molecular weight of from 250 to
5,000 and are typically finely divided through the
polymer matrix in a quantity of 0.01 to 2.0% by weight,
based on the interpolymer resin composition. The
interpolymer resin particles can also contain from 0.1
to 0.5% by weight based on the interpolymer resin,
talc, organic bromide-containing compounds, and polar
agents as described in WO 98/01489, which include
isalkylsulphosuccinates, sorbital-C8-20-carboxylates,
and 08-20- alkylxylene sulphonates.
In some embodiments of the invention, other
materials such as elastomers and additives can be added
in whole or part to the interpolymer resin particles.
In various embodiments of the invention, various
materials or additives are added to the interpolymer
resin particles so that it acts as a carrier for the
materials or additives.
In many embodiments of the invention, the
interpolymer can be processed (extruded, dried, etc.)
prior to use as a rheology modifier to remove any
moisture, unreacted volatiles or reaction decomposition
products from the interpolymer.
The interpolymer resin particles are generally
present in the rheology modified thermoplastic resin at
a level of at least about 0.1 wt.%, in some cases at
least about 0.5 wt.%, and in other cases at least about
1 wt.% and can be up to about 70 wt.%, in some cases up
to about 60 wt.% in other cases up to about 50 wt.% in
some instances up to about 40 wt.%, in other instances
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up to about 30 wt.% and in some situations up to about
25 wt.% of the rheology modified thermoplastic resin.
The amount of interpolymer resin particles in the
rheology modified thermoplastic resin will vary
depending on the particular thermoplastic resins and/or
elastomers in the rheology modified thermoplastic resin
and the end use. The amount of interpolymer resin
particles in the rheology modified thermoplastic resin
can be any value or range between any of the values
recited above.
In some particular embodiments, the rheology
modified thermoplastic resin is intended to be used in
thermoforming operations and the interpolymer resin
particles are present in the rheology modified
thermoplastic resin at a level of at least about 10
wt.%, in some cases at least about 12.5 wt.%, and in
other cases at least about 15 wt.% and up to about 50
wt.%, in some cases up to about 40 wt.%, in other cases
up to about 35 wt.%, in some instances up to about 30
wt.% and in other instances up to about 25 wt.% of the
rheology modified thermoplastic resin.
In other particular embodiments, the rheology
modified thermoplastic resin is intended to be used in
foam applications and the interpolymer resin particles
are present in the rheology modified thermoplastic
resin at a level of at least about 0.1 wt.%, in some
cases at least about 0.5 wt.%, and in other cases at
least about 1 wt.% and up to about 10 wt.%, in some
cases up to about 7.5 wt.% and in other cases up to
about 10 wt.% of the rheology modified thermoplastic
resin.
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In some embodiments of the invention, the rheology
modified thermoplastic resin can be made by preparing a
first blend of the interpolymer resin particles with
one or more first thermoplastic resins and/or
elastomers and then blending the first blend into one
or more second thermoplastic resins and/or elastomers.
The rheology modified thermoplastic resin can
optionally include, depending on its intended use,
additives and adjuvants, which can include, without
limitation, anti-blocking agents, antioxidants, anti-
static additives, activators, zinc oxide, colorants,
dyes, filler materials, flame retardants, heat
stabilizers, impact modifiers, light stabilizers, light
absorbers, lubricants, pigments, plasticizers, slip
agents, softening agents, and combinations thereof.
Suitable anti-blocking agents, slip agents and
lubricants include without limitation silicone oils,
liquid paraffin, synthetic paraffin, mineral oils,
petrolatum, petroleum wax, polyethylene wax,
hydrogenated polybutene, higher fatty acids and the
metal salts thereof, linear fatty alcohols, glycerine,
sorbitol, propylene glycol, fatty acid esters of
monohydroxy or polyhydroxy alcohols, phthalates,
hydrogenated castor oil, beeswax, acetylated
monoglyceride, hydrogenated sperm oil, ethylenebis
fatty acid esters, and higher fatty amides. Suitable
lubricants include, but are not limited to, ester waxes
such as the glycerol types, the polymeric complex
esters, the oxidized polyethylene type ester waxes and
the like, metallic stearates such as barium, calcium,
magnesium, zinc and aluminum stearate, salts of 12-
hydroxystearic acid, amides of 12-hydroxy-stearic acid,
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stearic acid esters of polyethylene glycols, castor
oil, ethylene-bis-stearamide, ethylene bis cocamide,
ethylene bis lauramide, pentaerythritol adipate
stearate and combinations thereof in an amount of from
0.1 to 2 wt.% of the rheology modified thermoplastic
resin.
Suitable antioxidants include without limitation
Vitamin E, citric acid, ascorbic acid, ascorbyl
palmitrate, butylated phenolic antioxidants, tert-
butylhydroquinone (TBHQ) and propyl gallate (PG),
butylated hydroxyanisole (BHA), butylated hydroxy-
toluene (BHT), and hindered phenolics such as IRGANOM
1010 and IRGANOX 1076 available from Ciba Specialty
Chemicals Corp., Tarrytown, NY.
Suitable anti-static agents include, without
limitation, glycerine fatty acid, esters, sorbitan
fatty acid esters, propylene glycol fatty acid esters,
stearyl citrate, pentaerythritol fatty acid esters,
polyglycerine fatty acid esters, and polyoxethylene
glycerine fatty acid esters in an amount of from 0.01
to 2 wt.% of the rheology modified thermoplastic resin.
Suitable colorants, dyes and pigments are those
that do not adversely impact the desirable physical
properties of the rheology modified thermoplastic resin
include, without limitation, white or any colored
pigment. In embodiments of the invention, suitable
white pigments contain titanium oxide, zinc oxide,
magnesium oxide, cadmium oxide, zinc chloride, calcium
carbonate, magnesium carbonate, kaolin clay and
combinations thereof in an amount of 0.1 to 20 wt.% of
the rheology modified thermoplastic resin. In
embodiments of the invention, the colored pigment can
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include carbon black, phthalocyanine blue, Congo red,
titanium yellow or any other colored pigment typically
used in the printing industry in an amount of 0.1 to 20
wt.% of the rheology modified thermoplastic resin. In
embodiments of the invention, the colorants, dyes and
pigments include inorganic pigments including, without
limitation, titanium dioxide, iron oxide, zinc
chromate, cadmium sulfides, chromium oxides and sodium
aluminum silicate complexes. In embodiments of the
invention, the colorants, dyes and pigments include
organic type pigments, which include without
limitation, azo and diazo pigments, carbon black,
phthalocyanines, quinacridone pigments, perylene
pigments, isoindolinone, anthra-quinones, thio-indigo
and solvent dyes.
Suitable fillers are those that do not adversely
impact, and in some cases enhance, the desirable
physical properties of the rheology modified
thermoplastic resin. Suitable fillers, include, without
limitation, talc, silica, alumina, calcium carbonate in
ground and precipitated form, barium sulfate, talc,
metallic powder, glass spheres, barium stearate,
calcium stearate, aluminum oxide, aluminum hydroxide,
glass, clays such as kaolin and montmorolites, mica,
silica, alumina, metallic powder, glass spheres,
titanium dioxide, diatomaceous earth, calcium stearate,
aluminum oxide, aluminum hydroxide, and fiberglass, and
combinations thereof can be incorporated into the
polymer composition in order to reduce cost or to add
desired properties to the rheology modified
thermoplastic resin. The amount of filler is desirably
less than 10% of the total weight of the rheology
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modified thermoplastic resin as long as this amount
does not alter the properties of the rheology modified
thermoplastic resin.
Suitable flame retardants include, without
limitation, brominated polystyrene, brominated
polyphenylene oxide, red phosphorus, magnesium
hydroxide, magnesium carbonate, antimony pentoxide,
antimony trioxide, sodium antimonite, zinc borate and
combinations thereof in an amount of 0.1 to 2 wt.% of
the rheology modified thermoplastic resin.
Suitable heat stabilizers include, without
limitation, phosphite or phosphonite stabilizers and
hindered phenols, non-limiting examples being the
IRGANOX stabilizers and antioxidants available from
Ciba Specialty Chemicals. When used, the heat
stabilizers are included in an amount of 0.1 to 2 wt.%
of the rheology modified thermoplastic resin.
Suitable impact modifiers include, without
limitation, high impact polystyrene (HIPS), SEEPS,
ethylene - methacrylate resins (EMA), styrene/butadiene
block copolymers, ABS, copolymers of C1-C12 linear,
branched or cyclic olefins, C1-C12 linear, branched or
cyclic alkyl esters of (meth)acrylic acid, styrenic
monomers, styrene/ethylene/butene/styrene, block
copolymers, styrene/ethylene copolymers. The amount of
impact modifier used is typically in the range of 0.5
to 25 wt.% of the rheology modified thermoplastic
resin.
Suitable ultra-violet light (UV) stabilizers
include, without limitation, 2-hydroxy-4-(octyloxy)-
benzophenone, 2-hydroxy-4-(octyl oxy)-phenyl phenyl-
methanone, 2-(2'-hydroxy-3,5'-di-teramylphenyl)
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benzotriazole, and the family of UV stabilizers
available under the trade name TINUVIN from Ciba
Specialty Chemicals Co., Tarrytown, NY, in an amount of
0.1 to 2 wt.% of the rheology modified thermoplastic
resin.
Suitable ultraviolet light absorbers, include
without limitation, 2-(2-hydroxypheny1)-21-i-benzo-
triazoles, for example, known commercial hydroxypheny1-
2H-benzotriazoles and benzotriazoles hydroxybenzo-
phenones, acrylates, malonates, sterically hindered
amine stabilizers, sterically hindered amines
substituted on the N-atom by a hydroxy-substituted
alkoxy group, oxamides, tris-aryl-o-hydroxyphenyl-s-
triazines, esters of substituted and unsubstituted
benzoic acids, nickel compounds, and combinations
thereof, in an amount of 0.1 to 2 wt.% of the rheology
modified thermoplastic resin.
Suitable softening agents and plasticizers
include, without limitation, cumarone-indene resin, d-
limonene, terpene resins, and oils in an amount of
about 2 parts by weight or less based on 100 parts by
weight of the rheology modified thermoplastic resin.
In embodiments of the invention, the components of
the rheology modified thermoplastic resin are combined
into a homogenous mixture by any suitable technique,
which can include without limitation, mixing extrusion
(compounding) and milling. The rheology modified
thermoplastic resin components are then blended in the
form of granules or in powder form, according to the
types of components, in a blender before plastification
and homogenization. Blending may be effected in a
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discontinuous process working with batches or in a
continuous process.
In embodiments of the invention, the components
can be mixed, for example, in an internal mixer of
Banbury type, in a single or twin-screw co-rotary or
counter-rotary extruder, or in any other mixer capable
of supplying sufficient energy to melt and fully
homogenize the mixture.
In particular embodiments of the invention,
production of the mixture resulting from the
composition can be done by mixing extrusion
(compounding) in a twin-screw extruder. Such a mixture
must be a uniform and homogenous mixture.
In embodiments of the invention, the mixed
rheology modified thermoplastic resin is extruded into
pellets obtained by cutting under cooling water; the
pellets, which will be stored for subsequent conversion
into items and parts. The conversion techniques used
are those of plastics processing such as, in
particular, injection if a cover is involved, and
having very different wall thicknesses between the tear
start zone and the support and fitting structural zone.
In embodiments of the invention, the rheology
modified thermoplastic resin compositions can be
extruded directly into sheet, or film, or any article,
without having to go through a pelletization step.
In embodiments of the invention, the components of
the rheology modified thermoplastic resin including any
optional additives can be combined by melt blending.
In other embodiments of the present method, either
method can include adding the rheology modified
thermoplastic resin to a first extruder and then
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combining with the optional additives in a second
extruder.
Regardless of which method is used, during the
blending step, the polyolefin and interpolymer resin
particles are typically intimately mixed by high shear
mixing to form the rheology modified thermoplastic
resin where the mixture includes a continuous
polyolefin phase and an interpolymer resin particulate
dispersed phase. The dispersed interpolymer resin
particles are suspended or dispersed throughout the
polyolefin continuous phase. The manufacture of the
dispersed interpolymer resin particulate phase within
the polyolefin continuous phase can require substantial
mechanical input. Such input can be achieved using a
variety of mixing means including extruder mechanisms
where the materials are mixed under conditions of high
shear until the appropriate degree of wetting, intimate
contact and dispersion are achieved.
Not wishing to be limited to any single theory, in
the present invention, polymer blends are used because
of their superior properties when compared with those
of the corresponding homopolymers. Part of the present
invention is an improved understanding of the role that
improved compatibility plays in the performance
properties of a polymer blend. Chemical modification
and copolymerization can allow the polymers to be more
compatible with each other compared with the
corresponding homopolymers. This points to the fact
that the intermolecular interactions between chemically
different polymers plays a major role. Basic
thermodynamic considerations allow for an understanding
of this problem in a more quantitative way.
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Gibbs free energy is a function of the change in
enthalpy, (AH) (interaction energy) and the change in
entropy (AS), and provides a quantitative indication of
the number of relative positions that the different
molecules can occupy. For a spontaneous process to
take place, this change has to be negative; i.e.,
AG mix = AM - TAS < 0
In the case of polyethylene and polystyrene, the
value of AG mix is positive because the interaction
energy is not strong enough to overcome the entropy
factors.
In particular embodiments as further described
below, the thermoplastic resins and/or elastomers and
interpolymer resin particles used to prepare the
present rheology modified resin are selected such that
the free energy of mixing for the thermoplastic resins,
elastomers and interpolymer resin particles is very low
(less than zero). In many embodiments of the present
invention, the solubility parameter of the components
of the thermoplastic resins and/or elastomers are
sufficiently similar to the solubility parameters of
the interpolymer resin particles to provide that the
resulting thermo-dynamic interaction parameter values
(x) for the admixture are less than 0.5.
The "free energy of mixing" is defined as AG=AH-
TAS, where G is the Gibb's free energy, H is enthalpy,
S is entropy and T is temperature. In simple terms,
when the free energy of mixing (AG) of two components
is a positive value, the two components are immiscible
and will separate. For example, in the hypothetical
instance where the thermoplastic resins and/or
elastomers and interpolymer resin particles are
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substantially immiscible components, they will tend to
partition, which can minimize any desirable rheology
modification of the thermoplastic resins and/or
elastomers. Also, LG for a binary mixture containing a
component 1 and a component 2 may be defined by the
following equation:
LG=RT[(n1 in X1+ n2 in X2)+ x n1X2]
where R is the gas constant, T is temperature, "x" is
the volume fraction of component 1 or 2, n is the
number of particles, and x ("chi") represents the
thermodynamic interaction parameter. The thermodynamic
interaction parameter (x or "chi") is defined as the
difference in the energy of mixing of components 1 and
2. This can be represented by the following equation:
X = (LEmix/RT)Vm
where Vm is the average molar volume ("reference
segment volume") and R and T are defined above. "Chi"
may also be defined as the difference in solubility
parameter (SP) of two materials.
X = Vm (.51 - 62)2/RT
where 6 is the Hildebrand solubility parameter. The
solubility parameter may be computed from a value known
as the cohesive energy density ("ced") of a material.
The "ced" is related to the heat of vaporization of a
material, that is, how much energy is required to
remove a single molecule from the bulk. For polymeric
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systems where the assumption that the entropy of mixing
is exceedingly small, the free energy expressions
reduce to the energy of mixing itself, that is AG - LE,
and a theoretical critical point exists where two
materials become immiscible (phase separate) when "chi"
is greater than 0.5. For regular solutions, (low
molecular weight species) this critical point has a
value of 2Ø So in the present invention, it is
desirable that the value of "chi" for the thermoplastic
resins and/or elastomers and interpolymer resin
particles mixture is less than 0.5.
To summarize, from first principles, the "ced" for
a bulk material can be computed. The "ced" is directly
related to the solubility parameter (6) as indicated
above. The thermodynamic interaction parameter "chi"
(X ) can be computed from the differences in the
solubility parameter (6) for each of the two materials.
"Chi" along with relative fractions of materials in a
mixture may be used to compute the free energy of
mixing (AG). If AG is a negative value, the mixture is
thermodynamically stable and phase separation should
not occur. Critical points for this condition are
values of "chi" of 0.5 and less for higher molecular
weight materials such as the polymeric components of
the thermoplastic resins and/or elastomers and
interpolymer resin particles. See as a non-limiting
example at page 10, line 35 to page 11, line 27 of U.S.
Patent No. 7,329,468.
In embodiments of the invention, the difference
between the solubility parameter of the interpolymer
resin particles and the solubility parameter of the
thermoplastic resins and/or elastomers is not more than
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1 (cal/cm3) [0.5 (J/cm3) 1/2] , in some cases not more
than 0.75 (cal/cm3) 1/2 [0.366 (J/cm3)1/2], and in other
cases not more than 0.75 (cal/cm3)1/2 [0.25 (J/cm3)1/2].
In embodiments of the invention, the difference
between the solubility parameters of the interpolymer
resin particles and the solubility parameter of the
thermoplastic resins and/or elastomers is not more than
1.5 (cal/cm3) 1/2 [0.5 (J/cm3)1/2], in some cases not more
than 1.3 (cal/cm3)1/2 [0.366 (J/cm3) 1/2], and in other
cases not more than 1.2 (cal/cm3)1/2 [0.25 (J/cm3)1/2].
In embodiments of the invention, the difference
between the solubility parameters of the components of
a thermoplastic resins/elastomer mixture and the
solubility parameter of the interpolymer resin
particles is not more than 1.2 (cal/cm3)1/2 , in some
cases not more than 1.0 (cal/cm3)1/2, and in other cases
not more than 0.75 (cal/cm3)1/2.
The exact solubility parameter of a particular
polymer can vary based on its exact composition, amount
of branching, molecular weight and molecular weight
distribution. As such, the solubility parameter (6)
for the interpolymer resin particles used in the
present invention can be at least about 7.7 (cal/cm3)1/2
[3.76 (J/cm3)1/2], in some cases at least about 7.75
(cal/cm3) 1/2 [3 . 78 ( j/cm3) 1/2,
j and in other cases at
least about 7.8 (cal/cm3) 1/2 [3.8 (J/cm3)1/2] and can be
up to about 9.3 (cal/cm3) [4.54 (J/cm3)1/2], in some
cases up to about 9.2 (cal/cm3) 1/2 [4.49 (J/cm3)1/2] and
in other cases up to about 9.1 (cal/cm3)1/2 [4.44
j/cm3) in] The solubility parameter (6) for the
interpolymer resin particles used in the present
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invention can be any value or range between any of the
values recited above.
The solubility parameter (6) for the thermoplastic
resins used in the present invention can be at least
about 7.7 (cal/cm3) 1/2 [3.76 (J/cm3) 1/2] , in some cases
at least about 7.75 (cal/cm3) 1/2 [3.78 (J/cm3)1/2] and in
other cases at least about 7.8 (cal/cm3)1/2 [3.8
j/cm3) 1/2
] and can be up to about 8.4 (cal/cm3)1/2 [4.1
j/cm3) 1/2,
j in some cases up to about 8.3(cal/cm3) 1/2
[4.05 (J/cm3)1/2] and in other cases up to about 8.2
(cal/cm3)1/2 [4 (J/cm3)1/2]. In particular embodiments,
the solubility parameter (5) for the thermoplastic
resins can be 7.9 (cal/cm3)1/2 [3.85 (J/cm3)1/2] or 8.1
(cal/cm3) 1/2 [3 . 95 ( j/cm3)1/2] = The solubility parameter
(6) for the thermoplastic resins used in the present
invention can be any value or range between any of the
values recited above.
The solubility parameter (5) for the elastomers
used in the present invention can be at least about 8.3
(cal/cm3) 1/2
[4.05 (J/cm3)1/2] and in some cases at least
about 8.4 (cal/cm3)1/2 [4.1 (J/cm3)1/2] and can be up to
=about 8.6 (cal/cm3)1/2 [4.2 (J/cm3)1/2] and in some cases
up to about 8.5(cal/cm3)1/2 [4.15 (J/cm3)1/2]. The
solubility parameter (5) for the elastomers used in the
present invention can be any value or range between any
of the values recited above.
The solubility parameter (6) for the styrenic
polymers of the interpolymer resin particles used in
the present invention can be at least about 8.5
(cal/cm3) 1/2 [4.15 (J/cm3) 1/2] , in some cases at least
about 8.6 (cal/cm3)1/2 [4.2 (J/cm3)1/2] and in other
cases at least about 8.7 (cal/cm3)1/2 [4.24 (J/cm3)1/2]
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and can be up to about 9.3 (cal/cm3)1/2 [4.54
j/cm3) 1/2,
j in some
cases up to about 9.2 (cal/cm3) 1/2
[4.49 (J/cm3)1/2] and in other cases up to about 9.1
(cal/cm3) 1/2 [4.44 (J/cm3)1/2]. In particular
embodiments, the solubility parameter (6) for the
styrenic polymers can be 9 (cal/cm3) 1/2 [4=39 j/cm3)1/2]
or 8.8 (cal/cm3)1/2 [4.29 (J/cm3) 1/2]. The solubility
parameter (6) for the styrenic polymers used in the
present invention can be any value or range between any
of the values recited above.
The solubility parameter (6) for the polyolefin of
the interpolymer resin particles used in the present
invention can be at least about 7.7 (cal/cm3)1/2 [3.76
j/cm3) 1j
/2, r in some cases at least about 7.75
(cal/cm3) 1/2 [3.78 (J/cm3)1/2] and in other cases at
least about 7.8 (cal/cm3) 1/2 [3.8 ( j/cm3)1/2,
j and can be
up to about 8.4 (cal/cm3)1/2 [4.1 (J/cm3)1/2], in some
cases up to about 8.3(cal/cm3)1/2 [4.05 (J/cm3)1/2] and
in other cases up to about 8.2 (cal/cm3)1/2 [4
(J/cm3)1/2]. In particular embodiments, the solubility
parameter (6) for the polyolefin can be 7.9 (cal/cm3)1/2
[3=85 j/cm3) 1/2]
or 8.1 (cal/cm3)1/2 [3.95 j/cm3)1/2]
=
The solubility parameter (6) for the polyolefins used
in the present invention can be any value or range
between any of the values recited above.
In embodiments of the invention, the thermodynamic
interaction parameter "chi" (X ), calculated for the
blend of thermoplastic resin (and optional elastomers)
and interpolymer resin particles can be up to 0.5, in
many cases less than 0.5, in some cases not more than
0.4 and in other cases not more than 0.3.
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The present rheology modified thermoplastic resins
can be used in applications such as blown film, cast
film, solid sheets, injection molded articles,
thermoformed articles, blow molded articles, rotomolded
articles, compression molded articles, foamed articles
and functional films. Under most processing
conditions, the rheology modified thermoplastic resin
provides good throughput rates, a good balance between
melt viscosity and elasticity properties, and good
processibility while maintaining desirable physical
properties such as strength properties, heat seal
properties, and optical properties that meet the needs
of the end user.
As a non-limiting example, the low shear viscosity
of the rheology modified thermoplastic resin is
sufficiently high under normal processing conditions to
provide thermoformed articles that are more uniform and
are stronger than articles made with the same
polyolefin in the rheology modified thermoplastic resin
and not containing the present interpolymer resin
particles.
In another non-limiting example, the rheology
modified thermoplastic resin provides a more desirable
balance of viscous and elastic properties under
processing and demonstrates better processibility and
higher throughput rates than the same polyolefin as in
the rheology modified thermoplastic resin and not
containing the present interpolymer resin particles.
Thus, the rheology modified thermoplastic resin
provides an adequate balance between viscous and
elastic properties and provides good processibility
while maintaining good physical properties such as
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strength properties, heat seal properties, and optical
properties.
In particular embodiments of the invention, the
rheology modified thermoplastic resin provides improved
bubble stability properties in blown film applications
compared to blown films not containing the dispersed
interpolymer resin.
Not wishing to be bound by any particular theory,
it is believed that the dispersed interpolymer resin
particles act to improve the rheological properties of
the thermoplastic continuous phase.
Prior art attempts to tailor the melt strength of
a polyolefin has typically included increasing the
number of long chain branches and/or high molecular
tails in the polymer. However, this structural change
will inherently affect the physical properties of the
resin and it may no longer be suitable for a desired
application.
In the present invention, a polyethylene-
polystyrene interpolymer resin is used and not only
provides the advantages of compatibilizing and
reinforcing the thermoplastic resin, but also
increasing the melt strength of the thermoplastic
resins and consequently, offering wider processing
windows for resins that are normally suitable for a
limited number of processes, and open up opportunities
for resins that were not and potentially delivering new
materials.
The polyethylene-polystyrene interpolymer resin
has a unique melt rheology that makes it an ideal
rheology modifier. In many instances, the tan(6) (the
ratio of the loss modulus over the elastic modulus) of
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the polyethylene-polystyrene interpolymer resin is
below 1 for all stresses and demonstrates excellent
shear thinning properties. This indicates that the
material acts mostly as an elastic component over a
broad shear range and can significantly contribute to
the modification of the rheology of certain carrier
thermoplastic resins, non-limiting examples being
polyolefins and SEC based polymers.
In embodiments of the invention, when the
polyethylene-polystyrene interpolymer resin is added to
a thermoplastic, and in particular, a polyolefin resin,
the melt strength is increased. Even when the
thermoplastic is suitable for foaming applications by
itself, addition of the polyethylene-polystyrene
interpolymer resin increases the processing window and
higher throughput rates can be achieved with the
resulting rheology modified thermoplastic resin.
In particular embodiments of the invention, the
rheology modified thermoplastic resins according to the
invention demonstrate a haul off force that is at least
about 5% higher, in some cases at least about 10%
higher, and in other cases at least about 15% higher
than the haul off force of the thermoplastic resin
without the interpolymer resin particles.
In other particular embodiments of the invention,
the rheology modified thermoplastic resins according to
the invention have a melt strength at least about 10%
higher, in some cases at least about 20% higher and in
other cases at least about 25% higher than the melt
strength of the thermoplastic resin without the
interpolymer resin particles.
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In these embodiments, haul off force can be
determined using a Rheometric Scientific SR5 rheometer
equipped with heated parallel plates with a glass
chamber placed around the sample and plates with 50
cc/min N2 flow. The Samples are trimmed at a gap of 1.1
mm and then set to 1.00 mm for testing. Testing
includes a frequency sweep at 190 C, followed by a
temperature ramp from 140 C to 230 C. The haul-off
force is recorded and the data of the average force at
each speed are fitted with an exponential equation: F
= A*Exp(-v/B)+C where F and v are the haul-off force
and speed; A, B, C are constants and can be obtained by
LLS fitting. The value of C is used as the melt
strength result for the sample.
In further particular embodiments of the
invention, the rheology modified thermoplastic resins
according to the invention have a spiral flow that is
at least about 30% higher, in some cases at least about
40% higher and in other cases about 50% higher than the
spiral flow of the thermoplastic resin without the
interpolymer resin particles.
Spiral Flow molding can be performed on a 33 ton
Vista Sentry injection molding machine (Cincinnati
Milacron, Batavia, OH) with a 50 gram maximum shot-
size. The sample material is introduced into the
machine and 15 "shots" are run and discarded. This
allows for the temperature and pressure to equilibrate
and to ensure homogenous mixing of the resin in the
molding machine barrel. After the 15 shots are molded
and discarded, 5 shots are run and measured. The
average flow length of the 5 shots are reported.
Machine parameters and setpoints are: Temperature,
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420 F; Pressure, 2200 psi (max); and Inject Time, 10
seconds.
The present invention will further be described by
reference to the following examples. The following
examples are merely illustrative of the invention and
are not intended to be limiting. Unless otherwise
indicated, all percentages are by weight.
EXAMPLES
In the following examples, the interpolymer resins
were prepared as described in Example 1 of U.S. Pat.
No. 7,411,024. The compounded rheology modified
thermo-plastic resin samples were prepared by
compounding polyethylene on a Leistritz twin screw
extruder (co-rotating, inter-meshing, 35/1 - L/D). Dry
blends containing the interpolymer resins (5% - 30%
wt.) and (70% - 95%) polyethylene were prepared in a
ribbon blender prior to compounding. Blends were
processed at temperatures between 190 and 230 C. In
some cases, vacuum was pulled from one or more of the
ports to extract unnecessary volatiles or by-products
from the mixtures. The materials were strand
cut/pelletized after being cooled with flowing tap
water.
Example 1
The following materials were prepared and melt
blended as described above in the ratios in the
following table. Measurements were made using a
Rheometric Scientific SR5 rheometer equipped with
heated parallel plates with a glass chamber placed
around the sample and plates with 50 cc/min N2 flow.
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Samples were trimmed at a gap of 1.1 mm and then set to
1.00 mm for testing. Testing included a frequency
sweep at 190 C, followed by a temperature ramp from
140 C to 230 C.
Polyethylene (P) samples:
P1 - LF 219 (low density polyethylene available
from NOVA Chemicals Corp., 6-7.8 (cal/cm3)(L5)
P2 - LF 218 (linear low density polyethylene
available from NOVA Chemicals, 6-7.9 (cal/cm3) '5)
P3 - 19G (high density polyethylene available from
NOVA Chemicals, 6-8.0 (cal/cm3) '5))
P4 - HDPE 5502 (high density polyethylene from
Chevron Phillips, 6-8.0 (cal/cm3) '5))
P5 - FP 120C (linear low density polyethylene
available from NOVA Chemicals, 6-7.9 (cal/cm3) '5)
P6 - FPs 1170 (linear low density polyethylene
available from NOVA Chemicals, 6-7.9 (cal/cm3) '5)
Polyethylene-polystyrene interpolymer resins
(PES):
PES1 - 30% EVA/70% (96.7/3.3 styrene/butyl
acrylate copolymer) , 6-9.0 (cal/cm3) '5
PES2 - 30% EVA/70% (90/10 styrene/butyl acrylate
copolymer) , 6-9.1 (cal/cm3)(L5
PES 3 - 70 wt.% ethylene-vinyl acetate copolymer
(EVA)/30 wt.% polystyrene, 6-8.4 (cal/cm3) '5
PES4 - 50% EVA/50% polystyrene, 6-8.7 (cal/cm3) '5)
PES5 - 30% EVA/70% polystyrene, 6-9.0 (cal/cm3)(L5)
G'/G" = crossover point frequency (rads/sec)
CV = complex viscosity (104 Pascal.sec)
F = frequency (rads/sec)
T6 = Tan(6)
ZSV = zero shear viscosity (104 Pascal = sec)
- 37 -
C
w
o
CI
cil
Sample P PES G'/G" ZSV F T5 CV
F T5 CV c'7;
un
A 100% P1 -- 21.7 1.53 0.1 3.04 9.51
100 1.01 0.402 w
B -- 100% -- 24.1 0.1 0.94
101 100 0.59 1.10
PES1
C 97% P1 3% 22.9 1.48 0.1 2.84 8.91
100 0.99 0.366
PES1
D 95% P1 5% 15.6 1.71 0.1 2.59
9.87 100 0.99 0.372
PES1
n
E 90% P1 10% 11.0 1.83 0.1 2.58
10.6 100 0.96 0.394 0
I.)
PES1
m
a,
F 80% P1 20% 8.57 2.08 0.1 2.5 12.0
100 0.94 0.426 q3.
w
0
PES1
I.)
1 G 97% P1 3% 16.7 1.57 0.1 2.77 9.25
100 0.99 0.370 0
H
H
w PES2
I
H
MN
H 95% P1 5% 13.5 1.85 0.1 2.66
10.7 100 0.99 0.408 1
PES2
co
Iv
n
1-i
cp
w
o
O-
w
-.4
-.4
C
w
=
CI
Sample P PES G'/G" ZSV F T5
CV F T5 CV cil
I 90% P1 10% 11.1 2.09 0.1 2.62
12.2 100 0.99 0.458 c'7;
un
w
PES2
J 80% P1 20% 8.21 2.32
0.1 2.33 12.7 100 0.95 0.438
PES2
K 90% P1 10% 18.9 1.71
0.1 2.8 10.2 100 1.01 0.411
PES3
L 90% P1 10% 60.5 1.97
0.1 2.83 11.7 100 1.02 0.478
PES4
n
M 100% -- -- -- 0.1 5.93
10.8 100 1.34 0.115 o
I.)
-.3
P3
m
a,
N 90% P3 10% -- 0.1
4.99 13.3 100 1.24 0.119 q)
w
o
1 PES1
"
w 0 100% -- -- -- 0.1 20.9
4.97 100 1.73 1.17 o
H
H
P2
'
H
iN
P 90% P2 10% -- --
0.1 11.7 6.58 100 1.57 1.23 1
o
PES1
co
Q 45% P2 10% -- 0.1 6.34
10.0 100 1.4 1.26
45% P3 PE51
R 50% P2 -- -- -- 0.1 8.84
7.71 100 1.52 1.20
50% P3
Iv
n
1-i
cp
w
o
O-
w
-.4
-.4
CA 02764930 2011-12-08
WO 2010/151352
PCT/US2010/027799
Herein, it is apparent from the data presented in
Example 1, the increase in zero shear viscosity, most
notably the shift of G'/G" crossover points, the
increase in complex viscosity and the increase in tan
(6), that the interpolymers perform as processing aids
and positively influence the rheology of the foaming
resins. In addition, the data suggests that
incorporation of interpolymers described in this
invention may broaden the foaming processability
window, suggesting a more forgiving foaming process.
Finally, it appears as the interpolymer resins also act
as compatibilizers, as exemplified by the comparison
between Samples Q and R, where PES1 enhances the
rheology of the blend of two incompatible LLDPE (P2)
and HDPE (P3) materials versus the blend of the same
two incompatible materials without PES1.
Example 2
Samples were prepared as described in Example 1
and the melt strength was determined at 190 C.
Sample P PES Melt Strength
, (cN)
100% P1 11.4
100% PES1 55.4
50% P1 50% PES1 26.0
The data show that the melt strength of the
polyethylene was too low, which leads to blowout in
film applications. The melt strength of the
Polyethylene-polystyrene interpolymer resin was too
high for processing. The blend provides a melt
strength that allows for no blowout during blown film
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operations, good processibility, and uniform foaming
and or thermoforming.
Example 3
The following blends were prepared as described
above and tested on a Rosand RH7 capillary rheometer.
Sample melts at 190 C were extruded through a 1 mm
diameter die (L/D=16:1). The piston speed was 1 mm/min,
and the haul-off speed started from 1 m/min and
increased 1 m/min steps. The haul-off force is recorded
and the data of the average force at each speed are
fitted with an exponential equation: F = A*Exp(-v/B)+C
where F and v are the haul-off force and speed; A, B, C
are constants and can be obtained by LLS fitting. The
value of C is used as the CHO melt strength result for
the sample. Since haul-off force is proportional to
melt strength, the data show that in the case of HDPE,
addition of said interpolymer will efficiently modify
the blend rheology and improve melt elasticity of the
base resin.
Haul-off Force (cN)
Haul-off 100% 90/10 85/15 80/20
Speed P4 P4/PES5 P4/PES5 P4/PES5
(m/min)
1 4.19 4.27 4.41 4.48
5 4.20 4.5 4.64 4.88
10 4.34 4.56 4.78 5.06
G'/G" 8.11 6.23 5.60 4.26
(rads/sec)
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Example 4
The following blends were prepared and tested as
described above.
Haul-off Force (cN)
Haul-off 100% P1 95/5 90/10 80/20
Speed P1/PES1 Pl/PES1 P1/PES1
(m/min)
1 2.41 2.75 3.04 3.19
2 3.94 4.00 4.14 4.35
3 4.25 4.34 4.65 4.68
Haul-off Force (cN)
Haul-off 100% P1 95/5 90/10 80/20
Speed P1/PES2 P1/PES2 P1/PES2
(m/min)
1 2.41 2.98 3.45 3.71
2 3.94 4.28 4.86 4.90
3 4.25 4.66 5.19 5.22
The melt flow characteristics of LDPE polymers
were enhanced through the incorporation of the
interpolymers according to the invention. The results
shown in this example demonstrate a greater haul-off
force for blends including the present interpolymer
resin compared to the virgin polyolefin, hence a higher
melt strength.
Example 5
Samples were prepared as described in Example 1
and Spiral Flow molding was performed on a 33 ton Vista
Sentry injection molding machine (Cincinnati Milacron,
Batavia, OH) with a 50 gram maximum shot-size. The
sample material was introduced into the machine and 15
"shots" were run and discarded. This was to allow for
temperature and pressure equilibrium and to ensure
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homogenous mixing of the resin in the molding machine
barrel. After the 15 shots were molded and discarded, 5
shots were run and measured. The average flow length of
these 5 shots was reported. Machine parameters and
setpoints were: Temperature, 420 F; Pressure 2200 psi
(max); and Inject Time, 10 seconds. The SEBS was
CALPRENE H-6120 (Dynasol Elastomers, S.A., Madrid,
Spain) and the SEEPS was Septon 4055 (Kuraray Co.,
Ltd., Okayama, Japan). All percentages are by weight.
Interpolymer Elastomer Spriral Flow Increase
Resin (wt%) (wt.%) In. (cm) (%)
V SEBS (100%) 20.0
PES 1 (20%) SEBS (80%) 33.3 67
X PES 1 (40%) SEBS (60%) 48.4 142
PES 1 (60%) SEBS (40%) 51.1 156
PES 4 (40%) SEBS (60%0 36.2 81
AA PES 4 (60%) SEBS (40%) 44.1 121
AB PES 3 (60%) SEBS (40%) 44.5 123
AC SEEPS 30.6
AD PES 1 (20%) SEEPS (80%) 59.4 94
AE PES 1 (40%) SEEPS (60%) 58.7 92
AF PES 1 (60%) SEEPS (40%) 51.4 68
AG PES 4 (40%) SEEPS (60%) 49.8 63
AH PES 4 (60%) SEEPS (40%) 49.5 62
Al PES 3 (60%) SEEPS (40%) 42.2 38
The combination of the present interpolymer resin
particles with SEBS or SEEPS significantly increased
the spiral flow, hence its rheological properties, of
the blend compared to SEBS or SEEPS alone. The
increased flow, or enhanced processing characteristics,
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offers an opportunity for faster cycle times, more
intricate design and thinner parts.
Example 6
This example demonstrates improved uniformity of
molded parts made using the present rheology modified
thermoplastic resin. Resin samples were prepared as
described in Example 1.
Sheet were extruded using a 4.5 inch 32-1 extruder
(Welex Inc., Blue Bell. PA) running @ 600 lbs./hr to
produce 0.050" to 0.063" sheet comprised of the
materials in the table below. The heat profile on this
machine ranges from 350 F to 450 F.
Deep-draw trays were produced at Tray-Pak on a
DT/Sencorp trim in place thermoformer (Sencorp Systems,
Inc. Hyannis, MA) running 4.5 to 6.0-shots/per-minute
on a nine cavity mold. The heat profile on this machine
ranges from 950 F to 1000 F. The speed (cylinders per
minute) and sheet thickness (ST) is indicated in the
table. The average bottom thickness (BT), bottom
corner thickness (BCT) and corner side wall thickness
(CSWT) and standard deviation (SD) were based on nine
measurements.
- 44 -
0
w
o
,..,
o
P4 PES 5 Speed ST Weight BT
BCT CSWT ,..,
v,
(wt%) (wt%) (cpm) (mil) (g) (mil)
(mil (mil) ,..,
w
v,
AJ 100 0 4.5 0.06 43.3 0.046
0.030 0.013 w
SD 2.3 SD
SD SD
0.010
0.010 0.003
AK 90 10 4.5 0.06 45.6 0.047
0.031 0.019
SD 1.6 SD
SD SD
0.004
0.004 0.001
AL 85 15 4.5 0.06 45.8 0.042
0.026 0.014 n
SD 2.0 SD
SD SD 0
I.)
0.004
0.004 0.001
m
AM 80 20 4.5 0.06 46.1 0.042
0.025 0.015 a,
ko
w
1 SD 1.8 SD
SD SD 0
,.1. 0.004
0.002 0.001 I.)
0
Crl
H
AN 80 20 4.5 0.06 45.9 0.044
0.028 0.013 H
1
IH
SD 1.4 SD
SD SD I.)
1
0.004
0.004 0.001 0
co
AO 90 10 6 0.053 41.5 0.034
0.022 0.017
SD 1.1 SD
SD SD
0.008
0.007 0.003
AP 90 10 6 0.050 39.0 0.037
0.029 0.016
SD 0.8 SD
SD SD Iv
0.006
0.005 0.002 n
,-i
AQ 85 15 6 0.050 39.5 0.042
0.029 0.012
cp
SD 0.7 SD
SD SD w
o
0.002
0.005 0.001 ,..,
o
'a
w
--.1
--.1
vD
vD
CA 02764930 2011-12-08
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PCT/US2010/027799
The data demonstrate the improved uniformity in
molded parts obtained using the present rheology
modified thermoplastic resin containing interpolymer
resin particles compared with using a thermoplastic
resin alone.
Example 7
Samples were prepared as described in Example 1
and a capillary test was done on a Kayeness LCR5000
capillary rheometer at 190 C. Shear viscosity (n) was
measured at the indicated shear rates (1/s); a 60 mil
diameter die with 120 entrance angle and 20:1 LID was
used. The materials tested were AR (100% P4); AS (100%
PES 1); AT (80/20 w/w P4/PES 1); AU (85/15 w/w P4/PES
1); and AV (90/10 P4/PES 1).
Shear AR fl AS n AT n AU I1 AV ri
Rate (Pa.S) (Pa.S) (Pa.S) (Pa.S) (Pa.S)
(l/s)
1000 374 297 365 369 369
701 465 390 456 460 461
502 573 491 563 568 569
299 789 723 772 785 787
199 1010 1000 1009 1012 1012
100 1511 1723 1532 1524 1524
58 2037 2563 2088 2070 2067
21 3589 5612 3792 3699 3682
10 5163 9260 5383 5333 5299
3.4 8634 19147 9700 9396 9345
This data set demonstrates excellent shear
thinning processability of the polyolefin/interpolymer
blends compared to the virgin polyolefin resin, which
is both beneficial for polyolefin sheet extrusion, blow
molding and thermoforming.
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Example 8
Samples were prepared as in Examples 1 and 3
except that polypropylene (PP, P4G2k-152, Flint Hills)
was used instead of polyethylene. Sample AV was 100%
PP and sample AU was 85% PP and 15% PES 5.
Measurements were made as described in Example 3
using a Rheometric Scientific 5R5 rheometer equipped
with heated parallel plates with a glass chamber placed
around the sample and plates with 50 cc/min N2 flow.
Samples were trimmed at a gap of 1.1 mm and then set to
1.00 mm for testing. Testing included a frequency
sweep at 190 C, followed by a temperature ramp from
140 C to 230 C.
Haul Off AV AV Haul AU AU Haul
Speed Stretch Off Force Stretch Off Force
(m/min) Ratio (cN) Ratio (cN)
1 4.2 1.57 4.2 1.88
2 8.9 1.70 8.9 2.19
3 13.1 1.73 13.1 2.27
4 17.8 1.80 17.8 2.37
5 22.0 1.79 22.0 2.45
6 26.7 1.81 26.7 2.51
7 30.9 1.87 30.9 2.54
8 35.6 1.85 35.6 2.57
9 39.8 1.86 39.8 2.58
10 44.5 1.89 44.5 2.59
Mean Melt 1.8 2.4
Strength
(cN)
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PCT/US2010/027799
AV AU
G' G" Tan(5) G' G" Tan(5)
(rad/s) (Pa) (Pa) (Pas) (Pa) (Pa) (Pas)
0.05 239 931 3.9 163 763 4.69
0.26 1389 3158 2.27 1076 2721 2.53
0.97 4584 7201 1.57 3770 6398 1.7
2.59 9738 11911 1.22 8320 10881 1.31
5.00 15086 15786 1.05 13179 14658 1.11
9.65 22326 20118 0.90 19920 18966 0.95
25.9 37320 26836 0.72 34076 25807 0.76
50.00 50335 30933 0.61 46618 30066 0.64
96.54 66549 34447 0.52 62381 33607 0.54
The haul-off force data indicate that
polypropylene rheology was modified and melt strength
was improved by 30% through addition of the present
interpolymer resin. The data shows higher tan(6)
values for the interpolymer containing blends compared
to the pure thermoplastic at equivalent frequencies
during a frequency sweep, allowing for faster extrusion
rates, faster thermoforming cycle times and better
quality parts.
Example 9
Samples were prepared as in Example 1 except that
polyethylene rotomolding resins RM341 and RM539 (NOVA
Chemicals Inc.) were used with PES1. Density (ASTM
D792), Impact (DYNATUP ASTM 3763), Tensile (yield
strength) (ASTM D638), Flex (flexural modulus) (ASTM
D790), and melt strength at 150 C were determined using
the method described in Example 3. For each sample, an
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CA 02764930 2011-12-08
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PCT/US2010/027799
ESCR condition B result of > 1,000 hours was obtained
(ASTM D1693).
RM341 RIVI539 PES1 Density Impact Tensile Flex Melt
(wt.%) (wt.%) (wt.%) (g/cm3) (lb.) (MPa) (MPa) (cN)
AW 100 0.9412 1662 21.8 877
0.80
AX 99 -- 1 0.9420 1587 21.2 890
0.89
AY 97 -- 3 0.9438 1503 21.2 928
0.90
AZ 95 -- 5 0.9441 1430
21.2 918 1.08
BA 90 10 0.9477 1454
20.6 909 1.87
BB -- 100 0.9331 1488
18.7 742 0.67
BC -- 99 1 0.9394 1557
19.3 764 0.59
BD -- 97 3 0.9410 1447
19.2 785 0.65
BE -- 95 5 0.9419 1525
19.3 772 0.67
BF -- 90 10 0.9450
1520 19.0 848 0.84
The data indicate that melt strength increases
with interpolymer content while physical properties of
the blends are not adversely impacted with the presence
of interpolymer resin. Impact properties do not appear
to change with increasing interpolymer resin content in
the rotomolding grade polyethylene, tensile properties
decrease slightly with increasing interpolymer content,
while flexural modulus increases with interpolymer
content.
Example 10
Samples were prepared as in Example 1 except that
polyethylene blow molding resins HB-W952-A ("W952") and
HB-L354-A ("L354" both from NOVA Chemicals Inc.) were
used with PES1 and PES2.
- 49 -
0
w
o
,..,
o
,..,
v,
BG 100% L354 BH 90% L354/10% PES1
BH 85% L354/15% PES1 ,..,
w
v,
w
Q G' G" Tan(o) G' G" Tan(5)
G' G" Tan(6)
(rad/s) (Pa) (Pa) (Pas) (Pa) (Pa) (Pas)
(Pa) (Pa) (Pas)
0.05 1190 1991 1.69 1608 2374 1.48
1784 2482 1.39
0.26 3872 5420 1.40 4882 6193 1.27
5128 6363 1.24
0.97 9103 11099 1.22 10881 12277
1.13 11332 10596 1.10
0
2.59 16492 18257 1.11 19186 19720
1.03 19795 19902 1.01 0
I.)
-.3
5.00 24115 24958 1.04 27492 26494 0.96
28283 26614 0.94 m
a,
ko
1
w
9.65 34800 33529 0.96 38984 35052 0.90 39846 34932
0.88 0
07
I.)
o 0
25.9 59101 50233 0.85 64526 51340 0.80
65288 50677 0.78 H
H
I
I
H
50.00 83256 63622 0.76 89195 64080
0.72 89657 62916 0.70 "
1
0
co
96.54 116250 7870 0.67 122470 77294 0.63 121730 75202
0.62
Melt Strength (cN) 8.21 9.59
10.04
Iv
n
1-i
cp
w
o
,..,
o
O-
w
--.1
--.1
vD
vD
C
o
o
BI 100% W952 BJ 90%
W952/10% PES1 BK 85% w952/15% PES1
G' G" Tan(5) G' G" Tan(o)
G' G" Tan(5)
(rad/s) (Pa) (Pa) (Pas) (Pa) (Pa) (Pa-s)
(Pa) (Pa) (Pa-s)
0.05 3521 4497 1.28 3988 4665 1.17 4153 4719
1.14
0.26 9529 10789 1.13 10301 10729
1.04 10531 10801 1.03
0.97 20053 20372 1.07 20899 19827 0.95 21206
12656 0.94
01 2.59 34160 31464 0.92
34643 30119 0.87 34884 29971 0.86
0
5.00 47947 41228 0.86 47881 38904 0.81 48160
38656 0.80
9.65 66446 52941 0.80 65436 49403 0.75 65535
48840 0.75
0
25.9 105770 73542 0.70 101950
67553 0.66 101770 66346 0.65
0
50.00 141450 87589 0.62 134860 80145 0.59 133690
78183 0.58
96.54 186020 100460 0.54 176030 90607 0.51 174520 88266 0.51
0
co
o
o
CA 02764930 2011-12-08
WO 2010/151352
PCT/US2010/027799
Addition of PES1 to the L354 polyethylene blow
molding resin increased the melt strength. This data
shows that the rheological properties of the blow
molding resin can be tailored using the present
interpolymer. The blends with W952 polyethylene blow
molding resin and PES1 achieved a fractional tan (6) at
lower frequencies than the blow molding resin alone,
indicating better melt strength, larger processing
window, and potential for other resins to be used in
this market.
Example 11
Extruded foam samples were made by blending P1 or
PS 1200 (polystyrene, INEOS-NOVA LLC, PS) with PES1 and
talc (Luzenac), pentane (Linde, purity > 99%), glycerol
monostearate (GMS, Pationic 1052A) in a 50 mm counter-
rotating twin-screw extruder at 20 kg/hr. Foam
cylinders were made using the conditions in the table
below, butane as blowing agent (BA), and had the
indicated physical properties.
Nominal refers to the extruder set temperature,
Melt (extr) refers to the temperature of the melt
measured by a thermocouple in the extruder, and Melt
(IR) refers to the temperature extrudate measured by an
IR probe.
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P1 PES1 Nom. Melt Melt BA
Density Modulus
(wt%) (wt%) ( C) (extr) (IR) (wt%) (Kg/m3) (MPa)
( C) ( C)
BL 100 -- 110 120 -- 4.5 59.9 1.08
BM 100 -- 100 109 -- 7.8 36.3 0.67
BN 100 -- 100 116 -- 3.8 105.4 3.08
BO 85 15 110 120 102 4.2 86.3 3.3
BP 85 15 110 119 100 7.6 39.5 0.81
BQ 85 15 105 115 95 5.5 54.1 0.98
BR 70 30 100 122 107 3.0 123.6 7.14
BS 70 30 100 113 98 5.3 58.3 1.87
BT 70 30 100 108 98 9.2 51.9 1.21
BU 70 30 100 107 95 11.5 36.0 0.81
PS PES1 Nom. Melt Melt BA
Density Modulus
(wt%) (wt%) ( C) (extr) (IR) (wt%) (Kg/m3) (MPa)
( C) ( C)
BL 100 -- -- 160 121 3.3 58.3 19.83
BM 100 -- -- 147 115 4.8 45.7 15.61
BN 100 -- 136 106 5.9 40.6 14.64
BO 85 15 161 126 3.3 61.9 21.98
BP 85 15 -- 148 -- 5.0 43.9 16.52
BQ 85 15 -- 140 110 6.5 37.5 11.83
BR 70 30 156 126 120 3.3 65.0 12.76
BS 70 30 120 150 116 4.9 44.5 12.48
BT 70 30 120 145 110 6.3 36.0 11.83
BU 70 30 110 139 108 6.3 37.1 10.50
The interpolymers according to the invention
blended with polyethylene provide lower density foams
with equivalent properties, or similar density foams
with superior properties compared to the virgin
polyethylene foam. The interpolymers according to the
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CA 02764930 2011-12-08
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PCT/US2010/027799
invention blended with polystyrene provide softer foams
at equivalent densities.
Example 12
This example demonstrates the addition of PES1 to
P5 and shows increased throughput.
The polyolefin based films were produced using a
Macro Engineering and Technology blown film line under
the following conditions:
Blow Up Ratio (BUR) = 2.5:1
Die Gap: 35 mil
Dual lip air ring
Film Gauge = 1 mil
Melt Temperature = 412 F
Line Speed = 71.8 ft/min.
Output = 40 lbs/hr.
Dart Impact was determined according to ASTM
D1709, Tear: according to ASTM D1922, and Tensile was
determined using an Instrumet 5 head universal tester.
Test speed was 20 inches/min and grip separation was
2.0 inches. Tensile secant modulus was determined
using an Instrumet 5 head universal tester Test speed
of 0.2 inches/min, grip separation was 2.020 inches.
Modulus was measured at 1% strain. WVTR was conducted
on a Permatran mocon unit. This analysis provided a
value for the transmission rate of water vapor through
a barrier in units of gm/100 in2/day or gm/m2/day.
Water was HPLC grade. Samples were run in duplicate.
OTR was conducted on a Ox-Tran Mocon unit. This
analysis provided a value for the transmission rate of
oxygen through a barrier in units of cc/100 in2/day or
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CA 02764930 2011-12-08
WO 2010/151352 PCT/US2010/027799
cc/m2/day. The oxygen used was ultra high purity,
99.99% pure. Samples were run in duplicate.
Property P5 90% P5/10% PES1
Dart Impact 282 421
(g/mil)
Tear - MD (g/mil) 313 220
Tear - TD (g/mil) 561 517
1% Sec Modulus - 176 278
MD (MPa)
1% Sec Modulus - 209 306
TD (MPa)
Tensile Break Str 34.4 45.6
- MD (MPa)
*Tensile Break Str 33 40.2
- TD (MPa)
Elongation at 445 588
Break - MD (%)
Elongation at 693 774
Break - TD (%)
Tensile Yield Str 10.7 12.8
- MD (MPa)
Tensile Yield Str 9.9 11.4
- TD (MPa)
Tensile Elong at 16 16
Yield - MD (%)
Tensile Elong at 20 15
Yield - TD (%)
Tensile Energy 1.2 2.39
(J) MD
Tensile Energy 1.72 2.36
(J) TD
WVTR (g/100 1.34 1.368
in2/day)
OTR (g/100 578.8 515.8
in2/day)
The results indicate that incorporation of PES1
enhances P5 stiffness properties. The data show that
blown films from the blend demonstrated enhanced
throughput performance and physical properties of the
film and antiblock characteristics.
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Example 13
Samples were prepared as in Example 1 except that
propylene copolymers (PC, N00-M00, Ineos) was used
instead of polyethylene. Sample BY was 100% PC and
sample BZ was 85% PC and 15% PES5.
Measurements were made as described in Example 1
using a Rheometric Scientific SR5 rheometer equipped
with heated parallel plates with a glass chamber placed
around the sample and plates with 50 cc/min N2 flow.
Samples were trimmed at a gap of 1.1 mm and then set to
1.00 mm for testing. Testing included a frequency
sweep at 190 C, followed by a temperature ramp from
140 C to 230 C.
Haul Off BY BY Haul BZ BZ Haul
Speed Stretch Off Force Stretch Off Force
(m/min) Ratio (cN) Ratio (cN)
1 4.19 3.12 4.19 5.24
2 8.89 2.97 8.89 4.80
3 13.08 2.94 13.08 4.96
4 17.79 2.97 17.78 5.12
5 21.97 2.97 21.97 5.13
6 26.67 3.07 26.68 5.15
7 30.86 3.07 30.86 5.20
8 35.57 3.11 35.57 5.21
9 39.75 3.11 39.75 5.17
10 44.46 3.13 44.46 5.20
Mean Melt 3.0 5.1
Strength
(CN)
The haul-off force data indicate that the
polypropylene copolymer rheology is modified and melt
strength is improved by 70% through addition of the
interpolymer resin, allowing for faster extrusion
rates, faster thermoforming cycle times and better
quality parts.
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Example 13
This example demonstrates the different
rheological patterns of a polystyrene - ethylene-co-
vinylene acetate copolymer compounded blend (prepared
using a Leistritz extruder as described above)of
similar composition to PES1 in terms of polystyrene and
ethylene-co-vinylene acetate copolymer composition.
The polystyrene was PS 1200 (INEOS-NOVA LLC) and the
EVA was NA 480 (Equistar Chemicals, LP) a 7:3 ratio to
simulate the PS/EVA ratio in PES1.
The capillary rheology results shown in the tables
below.
Shear PS n EVA ri UPES- PS/EVA
Rate (Pa.S) (Pa.S) 315 n blend n
(1/s) (Pa.S) (Pa.S)
1000 267 308 296.7 247.8
701 348 382.1 389.9 322.4
502 437.3 470.7 491.2 396.2
299 623.5 660.8 723.3 558.7
199 843.2 870.4 1000 790.7
100 1476.3 1310 1723.3 1371.3
58 2174.9 1903 2563.3 1974.7
21 4723.2 3673.6 5612 4003.7
10 7651.9 5552.7 9260.2 6246.8
3.4 15744 10411.3 19146.7 11528.7
The data demonstrate the synergistic behavior that
characterizes the rheology modification properties of
the interpolymers of the present invention compared
with compounded blends of a similar composition. The
data indicates that when melt compounded into a blend,
polystyrene (70%) and EVA (30%) exhibit an additive
relationship in terms of rheological performance
proportional to the PS and EVA content. Surprisingly,
the data show that the same composition in the form of
the present interpolymer resin particles provide
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synergistic rheological behavior compared to the
straight PS, straight EVA and a melt compounded blend
of both PS and EVA. The PS/EVA blend capillary rheology
also exhibits signs of melt fracture at shear rates
between 299 s-1 and 502 s-1, which is not observed for
the interpolymer compositions, hence demonstrating a
more shear stable composition for the interpolymer
structure.
The table below shows DMA data (w, G',G" and
tan(N) for the samples.
w G' G" tan(6)
rad/s Pa Pa
0.05 1267 2894 2.28
0.07 1731 3690 2.13
0.10 2346 4640 1.98
0.14 3169 5777 1.82
0.19 4226 7082 1.68
0.26 5595 8580 1.53
0.36 7278 10257 1.41
0.50 9377 12101 1.29
0.70 11937 14142 1.18
0.97 14960 16250 1.09
1.35 18483 18493 1.00
1.87 22480 20711 0.92
2.60 27047 23042 0.85
3.60 32003 25305 0.79
5.00 37561 27606 0.73
6.96 43658 29760 0.68
9.66 50211 31933 0.64
12.40 55485 33565 0.60
18.61 64474 36098 0.56
25.91 72308 38172 0.53
36.00 80548 40238 0.50
50.00 89040 42311 0.48
69.51 97865 44430 0.45
96.50 106710 46653 0.44
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The DMA data show that G' and G" intersect at the
(1.35, 1.851X104) crossover point and that the PS/EVA
blend material displays tan(5) values greater than 1 at
some shear rates. No intersect point is observed for
the PES1 interpolymer and throughout the rheology
spectrum, tan(5) values are below one, indicating the
superior rheological performance of the present
interpolymer compared to the blend of similar
composition as it relates to the ability to modify the
flow, or elasticity of the materials in the melt phase.
The present invention has been described with
reference to specific details of particular embodiments
thereof. It is not intended that such details be
regarded as limitations upon the scope of the
invention.
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